จำนวน Repository ( 26 )

การใช้กากมะพร้าว ตันข้าวโพดและเปลือกทุเรียนเป็นวัสดุประกอบชีวภาพทดแทนไม้ในแผ่นใยอัดความหนาแน่นปานกลาง
การใช้กากมะพร้าว ตันข้าวโพดและเปลือกทุเรียนเป็นวัสดุประกอบชีวภาพทดแทนไม้ในแผ่นใยอัดความหนาแน่นปานกลาง

This research aims to study the application of coconut meal corn cob and durian peel as wood-substituted biocomposites in medium density fiberboard. The fiber: urea formaldehyde glue: isocyanate glue with polymeric diphenymethane diisocyanate type (pMDI) ratio is equal to 1: 0.13: 0.003. The fibers are taken from coconut meal corn cob and durian peel that 7 ratios are used to all of fiber mixing. The fiberboard production use 130°C of temperature with 20 – 50 kg/sq.cm of compressive pressure with 8 minutes per piece of rate. Their fiberboards have 603 – 856 kg/m of density that was tested follow the TIS 876-2547 standard. Resulting the MM33 ratio (coconut meal fibers: corn cob fibers: durian peel fibers is equal to 0.33: 0.33: 0.33) and the CC50 ratio (coconut meal fibers: corn cob fibers: durian peel fibers is equal to 0.50: 0.25: 0.25) can pass the standard in physical properties and mechanical properties. Moreover their fiberboards have good thermal insulation.

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Influence of Plasma Treatment on the Flexural Properties of Geopolymer Composites
Influence of Plasma Treatment on the Flexural Properties of Geopolymer Composites

In recently years geopolymer or polysialate composites have been developed and applied for a variety of fields. They are known as inorganic matrices composites which are fabricated and cured at room temperature or thermoseted in a simple autoclave. Geopolymer composites provide an excellent opportunity for achieving the goal of producing low cost high temperature resistant composite. The aim of this study is an investigation and comparing the flexural properties of geopolymer composites after reinforcements were influenced by plasma treatment with original fibre fabric. And preliminary results of the improvement in tensile strength Young’s modulus elongation of E-glass fibre fabric due to plasma treatment are studied in this paper. Many reinforcements and geopolymer matrices are now available but our works are focused on geopolymer composite Q17 Q13K-1 combination with E-glass fibre fabric which was investigated fabrication procedures together with their specific properties of these materials have been evaluated compared and discussed.

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Mechanical Properties of Silica-Based Geopolymer Composites Cured at Ambient Conditions in Accordance with Size-Independent Method
Mechanical Properties of Silica-Based Geopolymer Composites Cured at Ambient Conditions in Accordance with Size-Independent Method

In this paper silica-based geopolymer matrix reinforced composites containing approximately 35 50 or 55 wt.% of carbon (HTS 5631 1600tex 24K TohoTenax) advanced basalt (BCF13-2520tex KV12 Int Basaltex) or electrical grade glass (E-glass: E2400P192 Saint-Gobain Vetrotex) roving fibers respectively were synthesized and fabricated at ambient conditions. The flexural properties of the resulting composites which are high toughness: the shear stress plays here a greater role in compared with other ceramic matrix composites were determined on a universal testing machine under three-point bending mode in accordance with novel size-independent method which based on testing specimens at different scale of sample height (H) to span length (L) ratios; The basic principles of the new size-independent approach are presented as well. Microstructures of composites were analyzed by means of scanning electron microscope (SEM) on perpendicular sections the images show the adhesion between the fibers and geopolymer matrix are very good and micro-cracks on both cross-sections and surfaces of geocomposites are determined as inborn defects of inorganic matrix composites.

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แผ่นเกราะโลหะกันกระสุน
แผ่นเกราะโลหะกันกระสุน

This research project aimed to analyze and design the pattern of a bulletproof metal armor plate as well as build a bulletproof metal armor plate for a small armored regular truck. The methodology consisted of the NIJ standard test and the finite element analysis. The bulletproof plates created were tested for a real firing. Their firing results were compared with those of NIJ-standard using a finite element program in this case applying with the program Ansys/Explicit Dynamic. SolidWorks program is employed as a tool to design and create 3D models of armor plates and bullets. The materials taken in the finite element simulation were SKD11 and SUS304 and the parameters utilized in the research were material types hardness values spacing between the plates and thickness. In the case of two armor plates stacked SKD11 material was designed for the first armor plate to be hit by the bullet. It served to destroy bullets. In addition the second armor plate made of SUS304 material served to absorb energy and obstruct the movement of bullets. For testing a 30-06 caliber M2 AP 166 Gr bullet was selected at a 0-degree angle and the velocities measured and set by the Ansys/Explicit Dynamic program were 901.7 m/s and 880 m/s respectively. The front plate made of SKD11 material with a thickness of 10 mm and the back plate made of SUS304 material with a thickness of 10 mm were fired 1 shot. The results showed that the bullet could penetrate the front armor plate but not penetrate the back-armor plate. In the NIJ 3 standard tests the shooting with a 7.62x51 mm NATO FMJ 148 Gr shell at a 0-degree angle for 5 times with velocities equal to 846.4 841.3 839.1 838.2 and 845.3 m/s was performed on the stacking front and back armor plates both made of SUS304 material with a thickness of 8 mm. The bullet velocity simulated by the Ansys program was 847 m/s resulting in the front plate having a bullet penetration and a slight bulge on the back plate. From the finite element simulation results and the actual test results it was found that the damage to the armor plates detected by both methods was consistent. Therefore the finite element program was selected to simulate the damage of armor plates resistant to penetration according to the NIJ standard Level 4. The results of the research could be concluded that the use of armor plates stacked with suitable different materials in multiple layers would affect the penetration resistance. Increased thickness and optimal spacing between the armor plates were important parameters in penetration resistance. Moreover it revealed that the higher the material hardness the better its ability to resist penetration. In particular this suggestion should be applied to the first armor plate or front armor plate.

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การศึกษาพารามิเตอร์ในการขึ้นรูปแผ่นเกราะเซรามิกส์รูปร่างหกเหลี่ยมกันกระสุน
การศึกษาพารามิเตอร์ในการขึ้นรูปแผ่นเกราะเซรามิกส์รูปร่างหกเหลี่ยมกันกระสุน

This research had two objectives that were to study parameters for forming bulletproof ceramic armor plates and to create a model of a bulletproof ceramic armor plate for small armored regular trucks. The parameters used to form a ceramic armor plate contain the thickness of the armor plate and the compressive strength which affects the density distribution of the green compact. A ballistic ceramic armor plate with a hexagonal shaped material was created as a concave bulletproof plate. Extrusion results displayed that the hexagonal material was formed at a very high density on the side surface of the armor plate but with uneven capacity distributed across the overall plate due to the friction occurring on the wall of the mold. The finite element method particularly at the Ansys/Explicit Dynamic tools were applied to analyse the damage of bulletproof plates. The model of a concave-shaped bulletproof plate was set for the SKD11material influencing the changes in the direction of the bullet firing when the bullet hit the bulletproof plate at a velocity of 880 m/s in accordance with the NIJ 4 standard. The bullet was made of tungsten carbide and the ceramic armor plate was built with a size of 300×300 mm and thicknesses of 14 16 18 and 20 mm. The bullet was fired into the center part and onto the curved surface of the ceramic plate. The result shows that the armor plate could not resistant to penetration. In this situation the direction of the bullets movement against the armor plate especially at a curved surface as a slope could result the deflection of the bullet direction as well as reduction of penetration capability.

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